Put attending college on hold (it was to be Fordham University in New York) to film Mean Girls (2004).

Was considered for the roles of Regina and Cady in Mean Girls (2004). These roles eventually went to Rachel McAdams and Lindsay Lohan, respectively.She began modeling at age 11.

Good friends with American Gun (2005) co-star Nikki Reed.

Correct pronunciation of her last name is "Sigh-Frid.".

In May 2008, she dressed up as "Alice" of "Alice in Wonderland" for a seven-page spread for Vogue Italia. That same month, she was also featured in the promotional poster for her movie musical Mamma Mia! (2008).

Originally auditioned for the title role on "Veronica Mars" (2004) but lost the part to Kristen Bell. Instead of playing "Veronica", she was offered the role of "Lilly", Veronica's dead best friend. She was so popular in this role, she was brought back more often than ever expected.As a child model, she initially signed with Image International Agency in Allentown, Pennsylvania before working under Bethlehem's Pro Model Agency and eventually with Wilhelmina agency in New York.

Beat several actresses for the role of "Sophie" in the film Mamma Mia! (2008). One of the actresses was fellow co-star Rachel McAdams who acted alongside Seyfried in the film Mean Girls (2004). In this film, McAdams beat Seyfried for the role of "Regina George".Auditioned for the lead role of "Kelli" for the horror remake Black Christmas (2006), but lost out to Katie Cassidy.Was in a relationship with Dominic Cooper, having met on the set of Mamma Mia! (2008) (October 2007-May 2010).Lost the part of "Babydoll" in Sucker Punch (2011) because she was committed to her HBO show "Big Love" (2006).One of People Magazine's 100 Most Beautiful People in the World (2009 and 2010).